<template>
    <div class="app-container">

        <!-- 课程信息表单 -->
        <el-form label-width="120px">

            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写" />
            </el-form-item>

            <!-- 课程讲师 -->
            <el-form-item label="课程讲师">
                <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                    <el-option v-for="teacher in teacherList" :key="teacher.id" :value="teacher.id"
                        :label="teacher.name" />
                </el-select>
            </el-form-item>

            <!-- 所属分类：级联下拉列表 -->
            <el-form-item label="课程类别">
                <!-- 一级分类 -->
                <el-select @change="subjectChanged" v-model="courseInfo.subjectParentId" placeholder="请选择">
                    <el-option v-for="subject in subjectList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>

                <!-- 二级分类 -->
                <el-select v-model="courseInfo.subjectId" placeholder="请选择">
                    <el-option v-for="subject in subjectLevelTwoList" :key="subject.id" :label="subject.title"
                        :value="subject.id" />
                </el-select>
            </el-form-item>

            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right"
                    placeholder="请填写课程的总课时数" />
            </el-form-item>

            <!-- 课程简介-->
            <el-form-item label="课程简介">
                <tinymce :height="300" v-model="courseInfo.description" />
            </el-form-item>

            <!-- 课程封面 -->
            <el-form-item label="课程封面">
                <el-upload :show-file-list="false" :on-success="handleCoverSuccess" :before-upload="beforeCoverUpload"
                    :on-error="handleCoverError" class="cover-uploader"
                    action="http://localhost:8120/admin/oss/file/upload?module=cover">
                    <img v-if="courseInfo.cover" :src="courseInfo.cover">
                    <i v-else class="el-icon-plus avatar-uploader-icon" />
                </el-upload>
            </el-form-item>

            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right"
                    placeholder="免费课程请设置为0元" /> 元
            </el-form-item>
        </el-form>

        <div style="text-align:center">
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveAndNext()">保存并下一步</el-button>
        </div>
    </div>
</template>

<script>

import courseApi from '@/api/course'
import teacherApi from '@/api/teacher'
import subjectApi from '@/api/subject'
// 富文本编辑器
import Tinymce from '@/components/Tinymce'

export default {
    components: { Tinymce },
    created() {
        if (this.$parent.courseId) { // 回显
            this.fetchCourseInfoById(this.$parent.courseId)
        } else { // 新增
            // 初始化分类列表
            this.initSubjectList()
        }
        // 初始化获取讲师列表
        this.initTeacherList()
        // 初始化分类列表
        this.initSubjectList()
    },
    data() {
        return {
            saveBtnDisabled: false, // 按钮是否禁用
            courseInfo: {// 表单数据
                price: 0,
                lessonNum: 0,
                // 以下解决表单数据不全时insert语句非空校验
                teacherId: '',
                subjectId: '',
                subjectParentId: '',
                cover: '',
                description: ''
            },
            teacherList: [], // 讲师列表
            subjectList: [],//一级分类列表
        }
    },

    methods: {
        // 保存并下一步
        saveAndNext() {
            this.saveBtnDisabled = true
            console.info("111" + this.$parent.courseId)
            if (!this.$parent.courseId) {
                this.saveData()
            } else {
                this.updateData()
            }
        },
        // 修改
        updateData() {
            courseApi.updateCourseInfoById(this.courseInfo).then(response => {
                this.$message.success(response.message)
                this.$parent.active = 1 // 下一步
            })
        },
        fetchCourseInfoById(id) {
            courseApi.getCourseInfoById(id).then(response => {
                this.courseInfo = response.data.item

                // 初始化分类列表
                // this.initSubjectList()
                subjectApi.getNestedTreeList().then(response => {
                    this.subjectList = response.data.items

                    // 填充二级菜单：遍历一级菜单列表，
                    this.subjectList.forEach(subject => {
                        // 找到和courseInfo.subjectParentId一致的父类别记录
                        if (subject.id === this.courseInfo.subjectParentId) {
                            // 拿到当前类别下的子类别列表，将子类别列表填入二级下拉菜单列表
                            this.subjectLevelTwoList = subject.children
                        }
                    })
                })
            })
        },
        // 上传成功回调
        handleCoverSuccess(res, file) {
            if (res.success) {
                // console.log(res)
                this.courseInfo.cover = res.data.url
                // 强制重新渲染
                this.$forceUpdate()
            } else {
                this.$message.error('上传失败1')
            }
        },

        // 上传校验
        beforeCoverUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },

        // 错误处理
        handleCoverError() {
            console.log('error')
            this.$message.error('上传失败2')
        },
        subjectChanged(value) {
            this.subjectList.forEach(subject => {
                if (subject.id === value) {
                    this.courseInfo.subjectId = ''
                    this.subjectLevelTwoList = subject.children
                }
            })
        },
        initSubjectList() {
            subjectApi.getNestedTreeList().then(response => {
                this.subjectList = response.data.items
            })
        },
        //获取讲师列表
        initTeacherList() {
            teacherApi.list().then(response => {
                this.teacherList = response.data.items
            })
        },
        // 保存并下一步
        saveAndNext() {
            this.saveBtnDisabled = true
            this.saveData()
        },

        // 保存
        saveData() {
            courseApi.saveCourseInfo(this.courseInfo).then(response => {
                this.$message.success(response.message)
                this.$parent.courseId = response.data.courseId // 获取courseId
                this.$parent.active = 1 // 下一步  
            })
        }
    }
}
</script>
<style>
.tinymce-container {
    position: relative;
    line-height: normal;
}

.cover-uploader .el-upload {
    border: 1px dashed #d9d9d9;
    border-radius: 6px;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.cover-uploader .el-upload:hover {
    border-color: #409EFF;
}

.cover-uploader .avatar-uploader-icon {
    font-size: 28px;
    color: #8c939d;
    width: 640px;
    height: 357px;
    line-height: 357px;
    text-align: center;
}

.cover-uploader img {
    width: 640px;
    height: 357px;
    display: block;
}
</style>
